In addition to the close relationship between community composition and available resources, the physical structure of the forest has often been cited as an important factor affecting patterns of arthropod diversity. The objective of this study was to evaluate the effect of two native tree species, differing in physical structure, on the diversity of araneofauna in the Pedro del Río Zañartu (Hualpén) Botanical Park. We estimated the abundance, diversity, similarity and structure of the arboreal spider community associated with the two native trees, Peumus boldus Mol. (boldo) and Luma apiculata (D.C.) Burret (arrayán). We sampled spiders from eight randomly selected trees of each species using entomological umbrellas with vegetation beating. Sampling was conducted monthly from March 2001 to June 2002. We collected a total of 1602 specimens belonging to 7 families. The most abundant families present on the two tree species were Anyphaenidae, Theridiidae and Araneidae. We obtained similar values for the diversity indices of both tree species (1.576 for boldo and 1.288 for arrayán). Cluster analysis based on Jaccard similarity did not indicate differences between spider guilds inhabiting either tree species. In this sense, spiders are not restricted by the arboreal structure of these native tree species, but may be affected by other environmental variables such as food availability.